Batu yaman: Perbedaan antara revisi

Kalsedon pernah disangka sebagai kriptokristalin kuarsa yang berserat<ref>Chalcedony mineral information and data. http://www.mindat.org/min-960.html</ref> namun kini diketahui kalsedon juga bersifat polimorf karena keberadaan moganit di dalamnya.<ref name="heany_1994" /><ref>Origlieri, Marcus. "Moganite: a New Mineral -- Not!" Lithosphere (1994). Aug. 2007 <http://fgms.home.att.net/moganite.htm {{Webarchive|url=https://web.archive.org/web/20080309094336/http://fgms.home.att.net/moganite.htm |date=2008-03-09 }}>.</ref><ref>Nickel, Ernest H., and Monte C. Nichols. "IMA/CNMNC List of Mineral Names." Materials Data. June 2007. Aug. 2007 <http://www.geo.vu.nl/users/ima-cnmmn/MINERALlist.pdf {{Webarchive|url=https://web.archive.org/web/20080530134400/http://www.geo.vu.nl/users/ima-cnmmn/MINERALlist.pdf |date=2008-05-30 }}></ref> Kadar moganit dalam satu sampel kalsedon cukup bervariasi, umumnya antara 5 hingga 20 persen.<ref name="heany_1992">Heaney, Peter J., and Jeffrey E. Post. "The Widespread Distribution of a Novel Silica Polymorph in Microcrystalline Quartz Varieties." Science ns 255 (1992): 441-443. JSTOR. Aug. 2007. Keyword: moganite</ref>